Parasitology

Question 0

Ascaris lumbricoides (giant roundworm)

Answer 0

Fecal-oral; eggs visible in feces under microscope (because they’re giant). causes Intestinal infection. Bendazoles or pyrantel pamoate

Question 1

Enterobius vermicularis (Pinworm)

Answer 1

fecal-oral transmission. Intestinal infection causing anal pruritus (diagnosed via the Scotch Tape test). Bendazoles or pyrantel pamoate (because worms are bendy)

Question 2

Strongyloides stercoralis

Answer 2

larvae in soil penetrate the skin. Intestinal infection causing vomiting, diarrhea, epigastric pain (may be peptic ulcer- like). Ivermectin or albendazole (STRONG ass roundworm burrowing all the way through skin into intestines and needing ALbendazole/ivermectin vs regular bendazole)

Question 3

Hookworms (Ancylostoma duodenale, Necator americanus)

Answer 3

Larvae penetrate skin. Intestinal infection causing anemia by sucking blood from intestinal walls. Bendazoles or pyrantel pamoate

Question 4

What are the intestinal Nematodes?

Answer 4

Enterobius vermicularis (pinworm), Ascaris lumbricoides (giant roundworm), Strongyloides stercoralis, Ancylostoma duodenale/Necator americanus (hookworms)

Question 5

What are the tissue Nematodes?

Answer 5

Onchocerca volvulus, Loa loa, Wuchereria bancrofti and Toxocara canis

Question 6

Onchocerca volvulus

Answer 6

female blackfly bite. causes hyperpigmented skin and river blindness (black flies cause black skin and black sight). Treat with IVERmectin (rIVER blindness)

Question 7

Loa loa

Answer 7

Deer fly, horse fly or mango fly. causes swelling in the skin, worm in conjunctiva. treat with diethylcarbamazine

Question 8

Wuchereria bancrofti

Answer 8

female mosquito. blocks lymphatic vessels to give elephantitis, which usually happens 9mo-1yr after bite. treat with Diethylcarbamazine

Question 9

Toxocara canis

Answer 9

fecal-oral route. visceral larva migrans. give albendazole/mebendazole.

Question 10

Nematode routes of infxn

Answer 10

Ingested: EAT (Enterobius, Ascaris, Toxacara)
Cutaneous: can get these into your feet from SANd (Strongyloides, Ancylostoma, Necator)
Bites: lay LOW to avoid getting bitten (Loa loa, onchocerca, Wuchereria)

Question 11

Cestodes?

Answer 11

Taenia solium, Diphyllobothrium latum and Echinococcus granulosus

Question 12

T. solium

Answer 12

ingestion of larvae from undercooked pork; causes intestinal infection; praziquantel
ingestion of eggs from other sources; cysticercosis/neurocysticercosis; praziquantel/albendazole for neurocysti

Question 13

Diphyllobothrium latum

Answer 13

ingestion of larvae from raw freshwater fish. causes vit. B12 deficiency (by competing for B12 in intestine). treat with praziquantel

Question 14

Echinococcus granulosus

Answer 14

ingestion of eggs from dog feces. Hydatid cysts in liver, causing anaphylaxis if antigens released (surgeons preinject with ethanol to kill cysts before removal). treat with albendazole before trying surgery.

Question 15

Trematodes?

Answer 15

Schistosoma and Clonorchis sinesis

Question 16

Schistosoma haematobium

Answer 16

snails are hosts and they can penetrate human skin. can lead to squamous cell carcinoma of the bladder. treat with praziquantel.

Question 17

Schistosoma mansoni and japonicum

Answer 17

snails are hosts and can penetrate skin of humans. Cause liver and spleen granulomas/fibrosis leading to eventual portal hypertension. praziquantel.

Question 18

Clonorchis sinensis

Answer 18

undercooked fish. Biliary tract inflammation causing pigmented gallstones. Associated with cholangiocarcinoma. Praziquantel.

Question 20

Protozoa_GI

Answer 20

Giardia lamblia, Entamoeba histolytica, cryptosporidium

Question 21

Protozoa- CNS

Answer 21

Toxoplasma gondii, Naegleria fowleri, Trypanosoma brucei

Question 22

Protozoa-Heme

Answer 22

Plasmodium (vivax/ovale, falciparum, malariae), Babesia

Question 23

Protozoa-Other

Answer 23

Visc: Trypanosoma cruzi, Leishmania donovani

STD- Trichomonas vaginalis

Question 24

Giardia lamblia

Answer 24

Transmission: cysts in water
Diagnosis: trophozites oor cysts in stool
Causes: GIardiasis-bolating, flatulence, fatty diarrhea in campers/hikers. “fatty ghiradelli”
TX: Metronidazole

Question 25

Entamoeba histolytica

Answer 25

Transmission: Cysts in water
Diagnosis: serology and/or trophozoites (with RBCs in cytoplasm) or cysts with unto 4 nuclei in stool. *histology with flask shaped ulcer
Causes: amebiasis- dysentery, liver abscess (anchovy paste). RUQ pain.
TX:Metronidazole / iodoquinol for asymp cyst passers

Question 26

cryptosporidium

Answer 26

Transmission: oocytes in water
Diagnosis:oocytes on AF stain
Causes: Severe diarrhea in AIDs. mild in others
TX: Prevention with filtering water. nitazoxanide in i-competent hosts

Question 27

Toxoplasma gondii

Answer 27

Transmission: cysts in meat (mostly); oocytes in cat feces crosses placenta (preggers avoid cats)
Diagnosis:
Causes: congenital =chroioretinitis, hydrocephalus, IC calcifications. reactivation in AIDs-> brain abscess seen in ring enhacning CT/MRI
TX:Sulfadiazine + pyrimethamine

Question 28

Naegleria fowler

Answer 28

Transmission:swimming in freshwater lakes ( like nalgene bottle filled with fresh water)-> cribiform plate entry
Diagnosis: amoebas in spinal tap
Causes: rapidly fatal meningoencephalitis
TX:Amp B for few survivors

Question 29

Trypanosoma brucei

Answer 29

Transmission: tsetse fly, painful bite
Diagnosis: blood smear
Causes: African sleeping sickness-enlarhed LNs, recurring fever (antigenic variation) somnolence, coma
sub-species: T b. rhodesiense, T b. gambiense
TX: Suramin for blood borne, melarsoprol for CNS penetration.

Question 30

Plasmodium (vivax/ovale)

Answer 30

Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites, ** red granules (schuffner stippling) though out RBC
Causes: 48 hr cycle tertian fever, w/ efevrs 1st/3rd day; dormant hypozoite in liver
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first); ** for vivax use primaquine for hypozoite (test G6PD)

Question 31

Plasmodium (falciparum)

Answer 31

Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites
Causes: severe, irregular fevers; parasitized RBCs occlude capillaries in brain ( cerebral malaria), kidneys, lungs
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first)

Question 32

Plasmodium (malariae)

Answer 32

Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites, rC
Causes: 72 hr cycle (quartan)
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first)

Question 33

Trypanosoma cruzi,

Answer 33

Transmission: Reduvid bug (“kissing bug” or feces depositied in painless bite.
Diagnosis:blood smear
Causes: Chagas disease -dilated cardiomyopathy, apical atrophy, megacolon, megaesophagus; predom SAmerica. Unilateral peri-orbital swelling (Romana sign) characterizes acute stage.
TX: Benznidazole or nifutimox

Question 34

Leishmania donovani

Answer 34

Transmission: Sandfly
Diagnosis: Mecrophages containing amastogotes
Causes: Visc leishmaniasis (kala-azar)-spiking fevers, HSMegaly, pancytopenia.
TX: Amp B, sodium stibogluconate

Question 35

Trichomonas vaginalis

Answer 35

Transmission: sexual-cannot exist outside body as cannot form cysts
Diagnosis: trophozoites on wet mount; strawberry cervix
Causes: Vaginitis= foul smelling, greenish dischrge +itching/burning
TX: metronidazole (& partner Ppx)